Butadiene extraction



Patented May 20, 1947 BUTADIENE EXTRACTION John W. Packie, Green Village, and Richard A. Given, Elizabeth. N. J., assigner-s to Standard i! Development Company, a corporation of Delaware Appucaugn August zo, 1942, serai No. 456,616 s calm. (c1. 26o-asis) This invention relates to improvements in the extraction of hydrocarbons and relates particularly to the extraction of dioleilns from mixtures of hydrocarbons consisting of saturated and unsaturated 'hydrocarbons and other low boiling compounds.

In the extraction of hydrocarbons, for example in the separation of unsaturated hydrocarbons from mixtures of saturated and unsaturated hydrocarbons together with other low boiling compounds, various solvents can be used as extractants but it has always been diilicult to remove all of the desired constituents from the mixture of hydrocarbons and also to obtain a pure extract containing only the desired constituents and not an extract containing a maior portion of the desired constituent and a substantial portion of the undesirable constituents that were present in the original hydrocarbon mixture.

It is an object of this invention to provide improvements in the method of extracting from amixture of hydrocarbons an unsaturated hydrocarbon in a substantially pure form.

Another object of this invention is to provide a method in which substantially all of the desired constituents are removed from the mixture of hydrocarbons and recovered in a substantially pure form.

These and other objects of the invention will be understood on reading the following description with reference to th'e drawing illustrating diagrammatically the iiow of materials.

For example, the separation of butadiene from liquid mixtures of hydrocarbons containing 4 carbon atoms to the molecule using an ammoniacal cuprous acetate solution as the solvent will be described but it is not intended to limit this invention to the separation and segregation of butadiene alone or the use of this particular solvent alone as the method may likewise be used for the separation of other compounds such as styrene, etc., using other preferential solvents. Referring to the drawing, the mixture of hydrocarbons is passed through pipe I into a turbine-type agitator 2, together with the solvent introduced into pipe I by means of pipe 3 that tract as will be hereinafter described. This mixture of solvent extract and hydrocarbons is intimately mixed in turbine-type agitator 2. The intimately mixed mixture is then passed through pipe 5 into the settling chamber B by means of a. plurality of pipes 1, 0, 9 and I0. This settling chamber is maintained at a temperature of about 18 F. and at a pressure of about 18 lbs. per square inch gauge. Cooling means may be provided by an outside jacket, not shown.

The mixture, in this settling chamber, separates into two phases, one a hydrocarbon phase and the oth'er an extract phase containing thel solvent with the butadiene dissolved therein. This solvent with butadiene and some undesired hydrocarbons dissolved therein is removed through pipe II and passed to turbine-type agiis then passed into turbine-type agitator I 8 where they are intimately contacted and then passed through pipe Il and a plurality of pipes I8 into is used to extract the butadiene. Into this pipe l is also introduced through pipe 4, hydrocarbons that have been removed from the solvent exsettler I9 where a separation takes place, the lower layer containing the solvent extract being passed through pipe 3 into pipe I and the upper layer of unabsorbed hydrocarbons being passed through pipe 20 by rmeans of pump 2l into line 2'2, through which a solvent substantially free of hydrocarbonsv is being passed to turbine-type agitator 23. The mixture of hydrocarbons and solvent is intimately contacted by means of this turbine-type agitator 23. This mixture then passes through pipe 24 and, by means of a plurality of pipes 25, into settler 26 where layer separation takes place and the upper layer substantially free of butadiene is removed through pipe 21 from the system, the lower layer of solvent with butadiene in solution passing through pipe I5 to the turbine-type agitator I 8.

Th'ese three absorption steps as carried out in tion with settlers B, I9 and 26, are maintained at temperatures below room temperature, that is, 18, 14 and 10 F. respectively and pressures of 18, 21 and 24 lbs. respectively per square inch gauge. It is obvious that lower temperatures and somewhat higher temperatures may be used and also that the pressure may be varied.

The solvent leaving settler 8, containing substantially all of the butadiene and some of the other hydrocarbons that were present in the charge hydrocarbon mixture, passes through pipe Il and, in turbine-type agitator I2 is intimately contacted with hydrocarbons, principally butadiene, that have been rejected from settler 28 and passed through cooler 29 by means of pipe 30. In this agitator l2 the butadiene is preferentially dissolved from the hydrocarbon phase and uncle sired hydrocarbons are preferentially rejected from the solvent phase. The mixture of hydrocarbon and solvent phases is passed through pipe 3l and a plurality of pipes 32 and is separated in settler 33. The temperature maintained in settler 33 is about 25 F. and the pressure is about l5 lbs. per square inch gauge. The hydrocarbon phase is passed through pipe 4, provided with pump 34, into pipe I. The solvent layer, obtained in settler 33, is passed through pipe 35 by means of pump 3S through heater 3l' and by a. plurality of pipes 38 to settler 28 where a temperature of about 80 F. and a pressure of 8O lbs. per square inch gauge is maintained, The elevated temperature maintained in settler 28 rejects substantially all of the rest of the undesired hydrocarbons from the solvent, together with some butadiene. This hydrocarbon phase is passed through pipe 30 into line Il and the solvent containing substantially all of the butadiene that was present in the charge hydrocarbon mixture is removed through pipe 39 and passed to the upper part of desorber 4D. Pipe 39 is provided with a reducing valve to lower the pressure to about l lbs. per square inch gauge. Steam is supplied to the lower part of the desorber by means of steam coil 4| in the lower part of the desorber Ml. The temperature here maintained is about 170o F, The solvent, substantially free of dissolved hydrocarbons, is withdrawn from the bottom portion of desorber 40 by means of pipe 42 and passed by means of pump 43 through chiller M to reduce the temperature to about 8 F. and through pipe 22 into turbine-type agitator 23. Substantially pure butadiene with some ammonia vapor is recovered from the upper part of the desorber 40 and passed through pipe l5 upward through the butadiene scrubber i6 wherein water, provided at the upper part by means of pipe al, removes substantially all of the ammonia from the butadiene. The washfwater is removed from the lower part of the scrubber by means of pipe 39 while pure butadiene is removed from the upper part by means of pipe 48 and is then liquefied as the desired product.

Where dioleiins are to be separated, other cuprous salt solutions may be used as the solvent and likewise where other compounds are to be separated, other preferential solvents may be used.

We claim:

l. In the liquid phase solvent extraction of an olen from a mixture of olelns and saturated hydrocarbons, the steps in which the hydrocarbon mixture is intimately contacted with` a preferential solvent for an olen in a plurality of stages, each stage consisting of a turbine-type agitator and a settling chamber, the solvent passing through the stages in progressively increasing concentration of the olen content and the hydrocarbon mixture passing through the stages in progressively decreasing content of the olefin, the solvent for the olefin first being intimately contacted with the said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, the solvent phase in each case after being separated is passed in contact with the hydrocarbon phase having a higher olen concentration than the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with a solvent phase having a lower oleiin content than the one from which it had been separated, the solvent phase after passing through the turbine-type agitator and settling chamber of the last stage, is heated and passed to a settling chamber to expel in the liquid phase substantially all hydrocarbons except the desired olen, the expolled hydrocarbons being separated from the solvent phase in the said settling chamber, the separated hydrocarbons being recycled to the solvent phase passing to the turbine-type agitator and settling chamber of the last stage, the olefin is expelled from the said solvent phase, from which substantially all of the hydrocarbons except the desired olefin had been expelled, by heating to a sufficiently high temperature to vaporize the olefin, and the olefin is water washed and liqueed.

2. In the liquid phase solvent extraction of a diolen from a mixture of diolens, oleflns and saturated hydrocarbons, the steps in vwhich theA hydrocarbon mixture is intimately contacted with a preferential solvent for a diolen in a plurality of stages, each stage consisting of a turbinetype agitator and a settling chamber, the solvent passing through the stages in progressively increasing concentration of the diolefin content and the hydrocarbon mixture passing through the stages in progressively decreasing content of the diolei'ln, the solvent for the dioleiin first being intimately contacted with the said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, the solvent phase in each case after being separated is passed in contact with the hydrocarbon phase having a higher diolen concentration thanv the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with said solvent phase having a lower diolen content than the one from which it had been separated, the solvent phase after passing through the turbine-type agitator and settling chamber of the last stage is heated and passed to a settling chamber to expel in the liquid phase substantially all hydrocarbons except the diolen, the expelled hydrocarbons being separated from the solvent phase in the settling chamber, the separated hydrocarbons being recycled to the solvent phase passing to the turbine-type agitator and settling charnber of the last stage, the dioleln is expelled from the said solvent phase from which substantially all hydrocarbons except the dioleiin had been expelled, by heating to a suiciently high temperature to vaporize the dioleiin, and the diolen is water 'washed and liquefied.

3. In the liquid phase solvent extraction of a diolen from a mixture of hydrocarbons containing a diolen, the steps in which the. hydrocarbon mixture is intimately contactedfwith an ammoniacal cuprous acetate solution in a plurality of stages, each stage consisting of a turbine-type agitator and a settling chamber, the ammoniacal cuprous acetate solution passing through the stages in progressively increasing concentration of the diolefln content andthe hydrocarbon mixture passing through the stages in progressively decreasing content of the diolen, the ammoniacal cuprous acetate solution acting as a solvent for the diolen iirst being intimately contacted with the said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, the ammoniacal cuprous acetate solution phase in each case after being separated is passed in contact with the hydrocarbon phase having a higher diolen concentration than the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with an ammoniacal cuprous acetate solution phase having a lower diolen content than the one from which it had been separated, the ammoniacal cuprous acetate solution phase after passing through the turbine-type agitator and settling chamber of the last stage is heated to expel in the liquid phase substantially all hydrocarbons except the diolen, the expelled hydrocarbons being separated from the solvent phase in a settling chamber, the separated hydrocarbons being recycled to the ammoniacal cuprous acetate solution phase passing to the turbine-type agitator and settling chamber of the last stage where the hydrocarbon phase is contacted with the ammoniacal cuprous acetate solution phase, the dioleiln is expelled from the said ammoniacal cuprous acetate solution, from which substantially all hydrocarbons except the diolefin had been expelled, by heating to a sufficiently high temperature to vaporize the diolefln and the dlolefin is Water washed and liquied.

4. In the liquid phase solvent extraction of butadiene from a mixture of butadiene, olens and saturated hydrocarbons, the steps in which the hydrocarbon mixture is intimately contacted Y with a preferential solvent for butadiene in a plurality of stages, each stage consisting of a turbine-type agitator and a settling chamber, the solvent passing through the stages in progressively increasing concentration of the butadiene content and the hydrocarbon mixture passing through the stages in progressively decreasing content of the butadiene, the solvent for the butadiene iirst being intimately contacted with the said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, thev solvent phase in each case after being separated is passed in contact with the hydrocarbon phase having a higher butadiene concentration than the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with the solvent phase having a lower butadiene content than the one from which it had been separated, the solvent phase after passing through the turbine-type agitator and settling chamber of the last stage is heated to remove in the liquid phase substantially all hydrocarbons except the butadiene, the removed hydrocarbons being separated from the solvent phase in a settling chamber, the separated hydrocarbon being recycled to the solvent phase passing to the turbine-type agitator and settling chamber of the last stage where the hydrocarbon phase is contacted with the solvent phase, the butadiene is expelled from the said solvent, from which substantially all hydrocarbons except the butadiene had been removed, by heating to a suiciently hig temperature to vaporize the butadiene and the butadiene is water washed and liqueiled.

5. In the liquid phase solvent extraction of butadiene from a mixture of hydrocarbons containing saturated and unsaturated hydrocarbons and butadiene, the steps which comprise intimately contacting the hydrocarbon mixture with an ammoniacal cuprous acetate solution in a plurality of stages, each stage consisting of a turbine-type agitator and a settling chamber, the ammoniacal cuprous acetate solution passing through the stages in progressively increasing concentration of the butadiene content and the hydrocarbon mixture passing through the stages in progressively decreasing content of the butadiene, the ammoniacal cuprous acetate solution first being intimately contacted with said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, the ammoniacal cuprous acetate solution phase in each case after being separated is passed in contact with the hydrocarbon phase having a higher butadiene concentration than the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with the solvent phase having a lower butadiene content than the one from which it had been separated, the ammoniacal cuprous acetate solution after passing through the turbine-type agitator and settling chamber of the last stage is heated to a temperature of F. at a pressure of 80 pounds per square inch, and passed to a settling chamber to expel and separate hydrocarbons other than butadiene in the liquid phase, and the residual ammoniacal cuprous acetate solution is then further heated to expel all of the butadiene.

6.` In the liquid phase solvent extraction of a diolen from a mixture of oleiins, diolens and saturated hydrocarbons, the steps in which the hydrocarbon mixture is intimately contacted with a preferential solvent for diolei'lns in a plurality of stages, each stage consisting of a turbine-type agitator and a settling chamber, the solvent passing through the stages in progressively increasing concentration of the diolefln content and the hydrocarbon mixture passing through the stages in progressively decreasing content of the diolen, the solvent for the diolefln rst being intimately contacted with the said hydrocarbon mixture in the turbine-type agitators and then separated in the settling chambers to form a solvent phase and a hydrocarbon phase, the solvent phase in each case after being separated is pas'sed in contact with the hydrocarbon phase having a higher diolen concentration than the hydrocarbon phase from which it was separated, the hydrocarbon phase in each case after being separated is contacted with the solvent phase having a lower dioleiln content than the one from which it had been separated, the solvent phase after passing through the turbine-type agitator and settling chamber of the last stage, is heated to remove in the liquid phase substantially all hydrocarbons except the dloleiin, the removed hydrocarbon phase being separated from the solvent phase in a settling chamber, the separated hydrocarbon phase being recycled to the solvent phase passing to the turbineetype agitator and settling chamber of the last stage where the hydrocarbon is again contacted with the solvent, and the diolefin is expelled from the said solvent phase, from which all hydrocarbons exceptl the: desired diolen has been expelled, by heating to a, suicently high temperature to vaporize the diolefin.

JOHN W. PACKIE. RICHARD A. GIVEN.

REFERENCES CITED The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 1,282,906 Mersereau Oct. 29, 1918 1,651,328 Edeleanu et al Nov. 29, 1927 Number 10 Number 8 Name Date Joshua, et al June 18, 1935 Van Dijck May 25, 1937 Haeuber et a1 Apr. 18, 1939 Hebbard et al. Feb. 6, 1940 Fasce Mar. 3, 1942 Ragatz Oct. 1, 1940 FOREIGN PATENTS Country Date Great Britain Apr. 13, 1933 "Great Britain Jan. 31, 1941 

